Puberty: What Published Guidance Supports

Key takeaways

• Typical start for girls: between ages 8 and 13
• Typical start for boys: between ages 9 and 14
• Most useful single change: Talk about body changes before they start, using correct names for body parts.
• Commonest mistake: Comparing a child's development to siblings or friends.
• See a doctor if any of the signs under "When to speak to a doctor" below apply to you.

What it is

The years when the body develops into an adult body, driven by rising sex hormones. It sits within Teen Health. The figures come from the bodies named at the foot of this page.

The numbers, in one place

What helps

These are the changes with the clearest evidence behind them. Start wherever it is easiest to start.

• Talk about body changes before they start, using correct names for body parts
• Help teens prepare with period products, deodorant and a plan for school
• Expect growth spurts and bigger appetites, and offer nutritious meals and snacks
• Keep yearly checkups, where the doctor tracks growth and development

What to avoid

What to steer clear of, and why it catches people out.

• Comparing a child's development to siblings or friends
• Teasing about voice changes, body shape or acne
• Ignoring signs that a teen is restricting food or exercising excessively to change body shape

In depth

Puberty begins in the brain. A region called the hypothalamus starts releasing a hormone in pulses that signals the pituitary gland to produce two more hormones. These travel to the ovaries or testes, which then make estrogen or testosterone. Those sex hormones drive the physical changes of puberty. What triggers the brain to start this process is not fully understood, but genetics, body weight and overall health all play a part, which is why the timing varies so much between children.

In girls, the first sign is usually breast buds, small tender bumps under the nipple, sometimes on one side first. Pubic hair, underarm hair and a growth spurt follow, and the first period usually comes about 2 to 3 years after breast development begins. In boys, the first sign is enlargement of the testicles, which is easy to miss. Pubic hair, penis growth, voice changes, facial hair and the growth spurt follow, with the boys' spurt typically coming later than girls'.

Doctors track puberty using stages of sexual maturity, often called Tanner stages, that describe breast, genital and pubic hair development. Puberty usually takes several years from start to finish, and emotional and social development continues alongside it. Mood swings, stronger interest in privacy and independence, new feelings of attraction and heightened self-consciousness are all common as hormones and the developing brain interact.

Signs and symptoms

• Breast buds in girls and testicular enlargement in boys
• Pubic and underarm hair, and body odor
• A rapid growth spurt and changes in body shape
• Oily skin and acne
• First period in girls, and voice changes and facial hair in boys
• Mood swings and a growing need for privacy

Causes and risk factors

• Genetics, including the age parents went through puberty
• Body weight, with higher body fat linked to earlier puberty in girls
• Chronic illnesses that may delay puberty
• Intense athletic training or undereating, which can delay periods
• Rarely, brain, hormone or genetic conditions that cause early or late puberty
• Possibly exposure to certain chemicals, which is still being studied

How it is checked

At yearly checkups, the doctor tracks height and weight on growth charts and checks puberty stages during the physical exam. A change in growth rate, such as a child suddenly growing much faster or slower than before, can be an early clue that puberty is starting early or is delayed.

If puberty seems early or late, tests may include an X-ray of the hand and wrist to estimate bone age, blood tests for puberty hormones and thyroid function, and sometimes a stimulation test to see how the pituitary responds. For early puberty, especially in boys or young girls, a brain MRI may be done to look for a cause. A pediatric endocrinologist usually leads this evaluation.

Treatment and support options

Watchful monitoring

Many children who start puberty a little early or late are simply at the edges of normal. Constitutional delay, in which a child develops later but normally, often runs in families and is the most common cause of late puberty, especially in boys. In these cases, the doctor may recheck growth and development every few months before deciding whether treatment is needed.

Treatment for early puberty

When puberty starts too early because the brain signals turn on early, called central precocious puberty, a pediatric endocrinologist may suggest medicines that pause puberty until a more typical age. This can help preserve adult height and ease emotional stress. Treatment is stopped when it is appropriate for puberty to resume. If another cause is found, that cause is treated.

Treatment for late puberty

If puberty is significantly delayed, the doctor may suggest a short course of hormone treatment to jump-start development, which can help a teen who feels distressed about being behind peers. When an underlying condition, such as a hormone deficiency, chronic illness or eating disorder, is the cause, addressing it is the main treatment.

Support for periods

Periods are often irregular for the first few years. Teaching teens to track their cycles, use period products comfortably and know when to change them helps. Over-the-counter pain relievers may ease cramps. If periods are very heavy, last longer than about 7 days or cause missed school, the doctor can check for problems such as bleeding disorders or anemia and discuss treatments.

Prevention

• Keep yearly checkups so growth and development are tracked
• Offer balanced meals with enough calcium and vitamin D for growing bones
• Encourage regular physical activity and enough sleep
• Talk openly about body changes, consent and privacy
• Teach good hygiene habits, including daily washing and deodorant

Day to day

Talking about puberty early and often, in small conversations rather than one big talk, makes it feel normal. Books written for different ages, and answering questions honestly and calmly, help children feel prepared. Both girls and boys benefit from learning about changes in all bodies, not just their own. Let your child know that development happens at different times and that there is no right pace.

Puberty can bring new tensions at home, as teens seek more independence and privacy. Respecting closed doors and personal space, while staying available to talk, helps maintain trust. Practical preparation, such as packing a small kit with period products, deodorant and a spare shirt for school, can prevent embarrassment. If your child seems very distressed about body changes, talk with their doctor.

For specific groups

Girls who start early

Girls who develop earlier than peers may face unwanted attention and teasing and are more likely to experience low mood and body image concerns. Extra support and conversations about boundaries and safety are especially important.

Boys who start late

Boys who are smaller or less developed than peers may feel self-conscious, particularly in sports and locker rooms. Reassurance that they will catch up, and checking with a doctor if there are no signs by 14, can help.

Children with chronic conditions

Conditions such as inflammatory bowel disease, celiac disease, cystic fibrosis or poorly controlled diabetes can delay puberty and growth. Managing the underlying condition well supports more typical development.

Questions to ask your doctor

• Is my child's development on track for their age?
• Are these signs early or late enough to need testing?
• What is my child's predicted adult height?
• Are my daughter's periods normal, and when should we worry?
• Is breast swelling in my son normal?
• How can I support my child emotionally through these changes?

More questions, answered

Is breast development in boys normal?

Yes, it is common. Many boys develop some breast swelling or tenderness during puberty due to normal hormone changes. It usually goes away within a few months to two years. See the doctor if it is large, painful, growing quickly or affects only one side with a hard lump.

How long are periods irregular after they start?

It is normal for periods to be irregular for the first couple of years while hormones settle. Cycles in teens commonly range from about 21 to 45 days. See the doctor if periods stop for more than 3 months, come more often than every 21 days, or are very heavy.

When will my child stop growing?

Girls usually reach their adult height a couple of years after their first period, while boys often continue growing into their later teens. Bone age X-rays can help predict how much growth remains.

Is it normal for one breast to grow faster than the other?

Yes. Breasts often develop at different rates, and one may be larger than the other for a time. They often even out, although some difference in size is common in adults.

What are wet dreams?

Wet dreams, or nocturnal emissions, are the release of semen during sleep. They are a normal part of puberty for boys and are not something that can or needs to be controlled. Explaining this ahead of time can reduce embarrassment.

Can puberty affect mood and sleep?

Yes. Hormone changes can contribute to mood swings, and the body clock shifts later, making it harder to fall asleep early. Persistent low mood or anxiety should be discussed with the doctor rather than assumed to be part of puberty.

Related topics

• Testosterone: What the Evidence Actually Says (Men's Health)
• Growth and Development: What the Evidence Actually Says (Children's Health)
• Acne: What Published Guidance Supports (Skin Health)
• Breast Cancer: Sorting the Evidence From the Noise (Cancer Awareness)

Where to go next

• Puberty: The Quick Reference
• What Puberty Is, and Why It Matters
• Puberty — the reference entry
• Teen Health: The Complete Guide
• HPV Vaccine: Sorting the Evidence From the Noise
• Teen Driving Safety: What the Evidence Actually Says

When to speak to a doctor

See your doctor if puberty starts before age 8 in girls or 9 in boys, there are no signs by 13 or 14, there is no period by age 15, or periods are very heavy or painful. Call 911 for severe sudden pain in the testicle or lower belly, or heavy bleeding with dizziness or fainting.

Where this comes from

• Eunice Kennedy Shriver National Institute of Child Health and Human Development — Puberty and Precocious Puberty
• MedlinePlus — Puberty
• American College of Obstetricians and Gynecologists — Your First Period

How this page was put together

Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarized or generalized beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.

Medical disclaimer

This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.